System of control



Oct. 13, 1936. E. M. BOUTON 2,057,511

SAYSTEM OF CONTROL I Filed Aug. 1924 2 Sheets-Sheet 1 WITNESSES: f 4 I IINVENTOR Zak 0N7. 504/ fan 23 BY A ATTORNEY Patented Oct. 13, 1936UNITED STATES PATENT OFFICE SYSTEM OF CONTROL Application August 14,1924, Serial No. 781,921

19 Claims.

My invention relates to systems of control and it has particularrelation to systems that are employed for elevators, hoists and similarapplications.

An object of my invention is to provide means for effecting moreaccurate control of an elevator car at each floor or landing, regardlessof load conditions, than has been possible in prior elevator-controlsystems.

Another object of my invention is to provide a variable-voltage systemof control wherein the voltage applied to the motor may be maintained ata constant value corresponding to a predetermined hoisting speed duringupward or downward travel, if desired.

A further object of my invention is to avoid the necessity of inchingthe elevator by insuring that the car shall always stop in such positionthat its floor and the landing floor shall be in substantially the sameplane, thus making a positive automatic landing stop.

Another object of my invention is to insure smooth and accurate controlof an elevator by means of a single hoisting motor and by maintaining anuninterrupted supply of energy to the motor at all times during normaloperation.

My invention will be described in connection with the accompanyingdrawings in which Figure 1 is a. diagrammatic representation of the maincircuits and apparatus embodying my invention;

Fig. 2 is a diagrammatic View of certain control features employed inconnection with the system of Fig. 1;

Fig. 3 represents a relay or contactor employed in connection with myinvention; and

Fig. 4 represents, diagrammatically, the relative positions of severalfloors to be served by the elevator and the relative location of certainshoes or armatures that are adapted to control the relays illustrated inFig. 3.

With reference to Figs. 1 and 2, my invention comprises, preferably, avariable-voltage system of control embodying a hoisting motor having aseparately excited field-magnet winding 2. A generator 3 is connected ina loop circuit with the motor and is also provided with a separatelyexcited field-magnet winding 4, which may be controlled, in a familiarmanner, by reversing switches 5, 6, l and 8. The generator is providedalso with a cumulative series field-winding 9 having propercharacteristics to insure a substantially constant generator voltage forany given excitation of the separately excited winding. The generator isdriven in a familiar manner by any suitable means, such as theillustrated induction motor Ill, and an exciter H is mounted on thegenerator shaft for the purpose of supplying the necessary constantvoltage for the control of various magnetic switches, field windings anda suitable electro-magnetic brake l2.

Variable excitation of the generator 3 is accomplished by means of anexternal resistor l3, portions of which are successively excluded fromcircuit by means of a plurality of field relays I4, |5, I6 and I1, in amanner to be hereinafter set forth. Another resistor 24 is provided tobe connected, by means of a relay 25, in parallel relation to theseparately excited generator field-winding 4. Various landing switches26 to 3|, inclusive,'of the well-known cam-operated type, are mounted onthe car for controlling the elevator car in accordance with its positionin the hatchway. Switches 26, 21, 28 and 29 are of the normally opencontact type while switches 30 and 3| are of the normally closed contacttype.

A retiring magnet 32 is associated with switches 26, 28 and 30 to holdthese switches in their normal positions, (switches 26 and 28 closed andswitch 30 open) during energization of the coil. A magnet 33 performs asimilar function with respect to switches 21, 29 and 3|.

The cams engageable with the rollers of these switches maintain them inthe same positions as does their coils until the movement of the cartoward the floor with which the cams are associated causes the rollersto move off the cams, thus allowing the respective switches to assumetheir normal position.

In Fig. 2, I have illustrated control connections for energizing theoperating coils of the floor relays 35 to 38, inclusive, of the typeillustrated in Fig. 3. The relays 35 to 38 are energized by means ofcontact members 4|, 42, 43 and 44, respectively, of the car-switch 45.

Referring to Fig. 3, it will be seen that each of these relays 35 to 38comprises an armature 45, an actuating coil 41, and a core 410. formedsubstantially H-shaped with legs 41b somewhat longer than the legs 41c.

Energization of the coil 41 causes attraction of the armature 46 andthus closes contact between contact members 460..

Relays 35 to 38 are mounted on the elevator car for movement therewith(see Fig. 4) past groups of magnetizable iron plates 52, 53 and 54, oneof these groups being associated with each floor past which the caroperates.

Plate 54 cooperates with relay 35 to effect a release of the armature 46as the relay passes the plate by diverting the magnetic flux in the core41a through the short path defined by legs 41c. Plates 5| to 53 performa like function for the remaining relays.

My invention will be best understood from the following description ofits operation. Assuming the car to be at the first-floor level and thecontrol apparatus in its illustrated and inoperative condition, the carmay be started toward the fourth floor, for example, by closure ofcarswitch contact members 55. The up direction relay 56 is therebyclosed, its operating coil being connected to the illustrated lineconductors, whereupon reversing switches 5 and 1 and brakereleasingrelay 51 are closed. The closure of switches 5 and 1 connects thegenerator field winding 4 in circuit with field resistor l3 across theexciter ll.

When the car switch is actuated to its fullspeed position, contactmembers 42 and 44 are closed to operate field relays 25, I5 and I6 andfloor relays 36 and 38. In addition to these field relays, auxiliaryrelays 59 and BI are closed for a purpose to be disclosed later. Theoperating circuit for these relays extends from the positive lineconductor through operating coils 62 to 65, inclusive, contact members42 and landing switches 30 and 3| (closed at this instant) to thenegative line conductor. The operating circuit for field relay i6 andfloor relay 3!! extends from the positive line conductor through coils61 and 68, car switch contact members 44 and landing switches 30 and 3|to the negative line conductor. Relay 59 operates to energize coils 32and 33 and thus causes switches 26, 21, 28 and 29 to close and switches30 and 3| to open.

Switch 26 completes a holding circuit for reversing switches 5 and 1independent of up relay 56. Switches 28 and 29 complete a circuit forrelay I1. However, relays 35 to 38 have completed self holding circuitsby Way of conductor 18 and are, therefore, maintained energizedindependent of switches 30 and 3|.

The operation of relay 25 disconnects resistor 24, which was previouslyin shunt to the generator field winding 4, thus increasing the fieldexcitation. The circuit for the separately excited field winding extendsfrom the positive line conductor, through conductor 90, reversing switch5, conductors 9| and 92, field winding 3, conductor 93, the coil ofrelay 34, conductors 94, and 96, reversing switch 1, conductor 91, andresistor l3 to the negative line conductor. The relay 25, therefore,normally completes a shunt circuit for the field winding betweenconductors 9| and 94. The closure of relays I5 and I6 effects furtherstrengthening of the generator field by excluding portions of resistor13 from circuit. Relay I1, closed through landing switch 28 or landingswitch 29 excludes another portion of resistor 13. Maximum fieldexcitation is in this manner provided for the generator 3 and the motorI is thereby accelerated to full speed. At this time, relay 34 isenergized by the current traversing the now fully excited field winding4 of the generator 3 and this relay completes a circuit for the retiringmagnets 32 and 33 independent of relay 59 to insure retirement of theswitches 35 to 38 when the field current reaches a predetermined value;in other words, when the car is operating under full speed conditions.

If it is desired to stop the elevator at the fourth fioor, the carswitch may be returned to its off position after the car, in its upwardtravel, passes the shoe 54 adjacent to the second floor. It should benoted that the movement of the car is now independent of the car switch,and as previously described aholding circuit for the up reversing ordirectional switches 5 and 1 extends from the positive line conductorthrough the operating coils of switches 5, 1 and 51, interlocks B-outand 1-in, landing switch 25, conductor 16 and knife switch 11 to thenegative line conductor. Interlocks G-out and B-in indicate thecorresponding in or out positions of the switches 5 and 1 to close theinterlocks.

The holding circuit for relays 25, I5, 59, BI and 36, extends throughrelay coils 62 to 65, relay 36, conductor 18 and knife switch 11 to thenegative line conductor. A holding circuit for relay i6, extends throughcoils 61 and EB, relay 38 and conductor 18. Therefore, high speedconnections are maintained until the car passes the shoe 54 adjacent tothe third floor. This shoe establishes a demagnetizing circuit andeffects the opening of relay 38. Field relay I6 is thereby de-energizedto insert a portion of resistor I 3 in the generator field circuit. Theelevator speed is thus reduced and when the car passes the shoe 53,below the fourth fioor, relay 35 is opened, which thereby permits relay25 to close and relays I5, 59 and BI to open. This operation of fieldrelays 25 and I5 effects further reduction in the generator fieldstrength to correspondingly reduce the car speed. The exact location ofthe demagnetizing shoes with respect to the distance from the fourthfloor depends upon the maximum car speed and the time required to effectslowdown, as will be understood.

When relay 34 opens, coils 32 and 33 are deenergized and the severallimit switches thus become efiective subject to the operation of theassociated cams to further slow down and stop the elevator. The openingof limit switches 28 and 29 efiects the opening of field relay l1 and,as the car approaches the fourth fioor level, limit switch 26 opens tode-energize the coils 5, 1 and 51 of reversing switches 5 and 1 andbrake relay 51, thus bringing the car to rest at the floor level.

The cumulative series winding 9 on the generator 3 compensates forvariations in the load to be lifted or lowered so that the car alwaysstops substantially level with the fioor. I find, however, that it isnecessary to compensate for the magnetization curve of the generatorfield on account of the hysteresis loop. That is to say, when startingfrom rest, a definite slow speed corresponding to the first operatingpoint is attained at a given field fiux which requires a field currentcorresponding to N12 ampereturns. When slowing down from high speed tothe first or low-speed point, to obtain the same definite speed the samefield flux (1 is produced at less ampere-turns, corresponding to N11.For this reason I provide means, comprising a relay l4, which isnormally closed in its lower position, to exclude a portion of fieldresistor l3 on the first point of the car switch. A field current I2thereupon traverses the generator fieldwinding.

During high-speed operation, relay 6| is closed through car-switchcontact members 42, whereupon relay [4 is picked up and maintains aholding circuit for itself, thereby inserting said portion of resistorl3 in circuit with the generator field winding to reduce the fieldcurrent to a value equal to I1. Thus the full field strength requiredupon the initial starting of the car is supplied and the field strengthis reduced when the car is operating under high speed conditions. Theself holding circuit for relay M is broken by the deenergization ofrelay 6! when the floor relay 35 (or 36) is opened as the car isstopped.

The series cumulative field-winding provides a flat compounding-effectso that the speed of the elevator motor at slow speed is substantiallyindependent of the load in the car. It will be understood, of course,that the load current varies from that required to lift a full car tothat which passes through zero and becomes a current of regeneration,when lowering a fully loaded car. This Wide variation in load tends toproduce poor speed regulation and raises a problem in elevator controlwhich has resulted in the production of control systems usually termedfloor-levelling systems. Such systems usually employ a separate sourceof power to insure accurate stopping and to return the car to thedesired level in case of overtravel. Such arrangements are undesirable,in passenger service, at least, because of the time lost inaccomplishing the desired result. It will be seen that, by the use of mysystem, overtravel is prevented and no levelling is required, inasmuchas an automatic or direct landing is efiected.

Downward movement of the car is effected in a manner similar to thatalready described upon the closure of down relay 19, which is controlledby car switch members 8| to operate reversing switches 6 and 8 and brakerelay 8B. When the car switch is actuated to close down contact members8|, 4| and 43 forthis direction of travel, the field relays arecontrolled through fioor relays 35 and 31, instead of through relays 36and 38, so that, in approaching a floor, high-speed relay 31 is firstopened to drop out field relay I6 and, thereafter, floor relay 35 isopened to de-energize the coils of field relays 25 and IS. Thefinal'slow-down and stop are thereafter made as previously described forthe upward movement of the elevator.

The motor cannot be plugged or reversed before reaching the desiredlanding because the limit switches 30 and 3| are open during fullspeedoperation. as previously traced, are maintained by relays 36 and 38, forupward travel, and by relays 35 and 31 for downward travel.

When it is desired to operate the elevator from one fioor to the nextadjacent floor, it is only necessary to momentarily actuate the carswitch, and the car, of course, does not attain its maximum speed in theshort distance to be traveled.

If, at any time, it is desired to operate the elevator in the ordinarymanner, entirely under control of the car switch, the double-throwknife-switch El should be actuated to its upper position, whereupon theautomatic operation of the floor relays and fioor limit switches isprevented. Relay 82 becomes effective to retire the limit switches bymaintaining coils 32 and 33 energized. This manual operation permitsvariable-voltage control that is, in the main, familiar to those skilledin the art and is employed in my system as a matter of convenience in.cases of emergency operation.

The proper holding circuits,

Whereas, the so' called levelling systems are not efficient inmaintaining a fast schedule of elevator operation, compared to ordinarymanual control by a skilled operator, my system of automatic control, inthe hands of an unskilled operator, has been found to accomplish aconsiderable saving in time over all previous systems of control becauseof the fact that the car never overtravels or undertravels, with respectto any landing.

A further advantage secured by the use of my invention is theelimination of mechanical contact between the car and the speed switchesor limit switches in the hatchway when slowing down from high speed. Thenoise and vibration of mechanical contact and occasional breakage ofparts is avoided.

- Obviously, modifications in my system will occur to those skilled inthe art and I desire that my invention shall be limited only inaccordance with-the scope of the appended claims.

I claim as my invention:

1. In a control system for an elevator operable between a plurality oifloors, motive means for moving said car, means for maintaining thespeed of said motive means constant under varying load, means forstarting said motive means and means for automatically initiating astopping of said motive means at such points in the travel of saidelevator as is required to decelerate and stop said elevator level withsaid fioors.

2. In a control system for elevators operable between a plurality offloors, an elevator, variable voltage driving means for moving saidelevator, having constant speed characteristics I under varying load,means for starting said motive means, and'means independent of saidstarting means for initiating a deceleration of said motive means atsuch points in the travel of said elevator as will permit said elevatorto stop level with the fioors regardless of the load on said elevator.

3. In a control system for elevators operable between a plurality offloors, multi-speed motive means for moving said elevator, means formaintaining the speed of said motive means constant under varying load,and'means operable in correspondence with movements of said elevator fordecelerating said motive means in steps of diminishing speed to causesaid elevator to stop level with said floors.

4. In a control system for elevators operable between a plurality offloors, multi-speed motive means for driving said elevator, means formaintaining the speed of said motive means constant under varying load,and electromagnetic means operable in correspondence with movements ofsaid elevator for decelerating said motive means in steps of diminishingspeed to cause said elevator to stop level with said floors.

5. In a control system for elevators operable between a plurality offloors, multi-speed motive means for moving said elevator, means formaintaining the speed of said motive means constant under varying load,and means for decelerating said motive means in steps of diminishingspeed to cause said. elevator to stop level with said floors, said lastnamed means comprising a 6. In a control system for elevators operablebetween a plurality of floors, multi-speed motive means for moving saidelevator, means for maintaining the speed of said motive means constantunder varying load, and means for decelerating said motive means insteps of diminishing speed to cause said elevator to stop level withsaid floors, said last named means comprising two elements, oneincluding a switch and a coil normally ineffective to actuate saidswitch, the other comprising means for rendering said coil effective toactuate said switch, and means for mounting said elements for relativemovement in correspondence with movements of said elevator.

7. In a control system for elevators operable between a plurality offloors, multi-speed motive means for moving said elevator, means formaintaining the speed of said motive means constant under varying load,and means for decelerating said motive means in steps of diminishingspeed to cause said elevator to stop level with said floors, said lastnamed means comprising a switch, means for actuating said switch, meansfor rendering said actuating means ineffective, and means for causingrelative movement between said actuating means and said means forrendering said actuating means inefiective, in correspondence withmovements of said elevator.

8. In a control system for elevators operable between a plurality offloors, multi-speed motive means for moving said elevator, means formaintaining the speed of said motive means constant under varying load,and means for decelerating said motive means in steps of diminishingspeed to cause said elevator to stop level with said floors, said lastnamed means comprising a switch, means for actuating and maintainingsaid switch, means for rendering said actuating means ineffective, andmeans for causing relative movement between said actuating means andsaid means for rendering said actuating means ineffective, incorrespondence with movements of said elevator.

9. In a control system for elevators operable between a plurality offloors, multi-speed motive means for moving said elevator, means formaintaining the speed of said motive means constant under varying load,and means for decelerating said motive means in steps of deminishingspeed to cause said elevator to stop level with said floors, said lastnamed means comprising a switch, magnetic means for actuating andmaintaining said switch, means for rendering said actuating meansineffective, and means for causing relative movement between saidactuating' means and said means for rendering said actuating meansineffective, in correspondence with movements of said elevator.

10. In a control system for elevators operable in a hatchway between aplurality of floors, multi-speed motive means for moving said ele vator,means for maintaining the speed of said motive means constant undervarying load and means operable in correspondence with movements of saidelevator for decelerating said motive means in steps of diminishingspeed to cause said elevator to stop level with said floors, said lastnamed means comprising a switch and a coil for actuating and maintainingsaid switch carried by said elevator, and a magnetizable plate carriedby said hatchway for rendering said coil ineffective to maintain saidswitch in actuated position.

11. A control system for elevators comprising in combination, a hoistingmotor, a reversing switch provided with a winding having a selfholdingcircuit, normally closed contactors in said self-holding circuit, andmeans to open said contactors having an energizing and a magnetizableelement, said elements movable into and out of attractive relation bycar movement, and effective when brought into attractive relation toopen said contactors.

12. A control system for elevators comprising in combination, a car, ahoisting motor, a plurality of landings, up and down reversing switcheshaving windings and self-holding circuits therefor, contactors in theself-holding circuit of the up switch, contactors in the selfholdingcircuit of the down switch, and means to actuate said contactors havinga magnetizing and magnetizable element, said elements brought into andout of attractive relation by movement of the car.

13. A control system for elevators comprising in combination, a hoistingmotor, a switch mechanism controllable manually to initiate car startshaving a winding provided with a self holding circuit, said windingmaintaining said switch mechanism closed independently of manualoperation, contactors in said self-holding circuit, and means to actuatesaid contactors comprising magnetizing and magnetizable ele ments, saidelements brought into and out of attractive relation by movement of thecar.

14. A control system for elevators, comprising in combination, a switchclosable manually having a winding and a self-holding circuit tomaintain said switch closed independently of manual operation,contactors in said self-holding circuit, and means to actuate saidcontactors comprising an electro-magnet and a member magnetizablethereby, said elements movable into and out of attractive relation inaccordance with car position.

15. A control system for elevators comprising in combination, a carstart switch, a car stop switch, a reversing switch winding having acircuit responsive to said car start switch, a selfholding circuit forsaid winding, said stop switch being in said self-holding circuit, andactuating means for said stop switch having a magnetizing andmagnetizable member movable into and out of attractive relation bymovement of the car.

16. A control system for elevators comprising in combination, a hoistingmotor, means to maintain a circuit therefor closed automaticallycomprising a switch having a winding provided with a self-holdingcircuit, contactors in said circuit, and actuating means for saidcontactors comprising a magnetizing and a magnetizable member movableinto and out of attractive relation by car movement.

17. A control system for elevators comprising in combination, a hoistingmotor, a reversing switch having a winding provided with a selfholdingcircuit, contactors in said circuit, and means to actuate saidcontactors comprising a magnetizable and a magnetizing element movableinto and out of attractive relation by car movement.

18. A system of control for elevators, comprising in combination thecar, motive means, control means comprising contactors effective tocause stop of the motive means but ineffective to cause start thereof,and actuating means for said contactors having a winding energizable topredetermine car stop and means controllable in accordance with carposition to form, a path for the magnetic lines of said winding so thatthe latter when energized is effective to actuate said. contactors onlywhen in attractive relation with said means.

19. A control system for elevators comprising in combination, a hoistingmotor, a switch mechanism having a winding energizable manually, saidwinding having a self-holding circuit, and means effective to open saidself-holding circuit comprising an eiectro-responsive switch partstationary and part movable in accordance with car movement.

EDGAR M. BOUTON.

